arch/x86/boot/bitops.h

   1 /* -*- linux-c -*- ------------------------------------------------------- *
   2  *
   3  *   Copyright (C) 1991, 1992 Linus Torvalds
   4  *   Copyright 2007 rPath, Inc. - All Rights Reserved
   5  *
   6  *   This file is part of the Linux kernel, and is made available under
   7  *   the terms of the GNU General Public License version 2.
   8  *
   9  * ----------------------------------------------------------------------- */
  10
  11 /*
  12  * Very simple bitops for the boot code.
  13  */
  14
  15 #ifndef BOOT_BITOPS_H
  16 #define BOOT_BITOPS_H
  17 #define _LINUX_BITOPS_H         /* Inhibit inclusion of <linux/bitops.h> */
  18
  19 #include <linux/types.h>
  20 #include <asm/asm.h>
  21
  22 static inline bool constant_test_bit(int nr, const void *addr)
  23 {
  24         const u32 *p = (const u32 *)addr;
  25         return ((1UL << (nr & 31)) & (p[nr >> 5])) != 0;
  26 }
  27 static inline bool variable_test_bit(int nr, const void *addr)
  28 {
  29         bool v;
  30         const u32 *p = (const u32 *)addr;
  31
  32         asm("btl %2,%1" CC_SET(c) : CC_OUT(c) (v) : "m" (*p), "Ir" (nr));
  33         return v;
  34 }
  35
  36 #define test_bit(nr,addr) \
  37 (__builtin_constant_p(nr) ? \
  38  constant_test_bit((nr),(addr)) : \
  39  variable_test_bit((nr),(addr)))
  40
  41 static inline void set_bit(int nr, void *addr)
  42 {
  43         asm("btsl %1,%0" : "+m" (*(u32 *)addr) : "Ir" (nr));
  44 }
  45
  46 #endif /* BOOT_BITOPS_H */